Lithium-sulfur　(Li-S)　batteries　are　considered　as　one　of　the　most　promising　energy　storage　systems.　However,　the　poor　electrical　conductivity　of　sulfur　and　Li2S,　sluggish　sulfur　redox　kinetics,　shuttle　effect　of　soluble　lithium　polysulfides　(LiPSs),　and　dendrites　growth　on　Li　anode　severely　preclude　their　practical　applications.　Herein,　a　heterostructured　Ni3Se4/FeSe2　tandem　electrocatalyst　directly　grown　on　the　electrospun　carbon　nanofibers　(denoted　as　CNF@Ni3Se4/FeSe2)　is　demonstrated　to　efficiently　capture　soluble　LiPSs　and　catalyzing　their　consecutive　conversion.　The　designed　CNF@Ni3Se4/FeSe2　interlayer　possesses　various　advantages　including　high　electrical　conductivity,　abundant　catalytic　active　sites,　strong　chemisorption　capability,　and　superior　catalytic　activities.　Furthermore,　theoretical　calculations　not　only　confirm　that　the　formation　of　Ni3Se4/FeSe2　heterostructure　is　beneficial　for　fast　charge　transfer　and　enhanced　LiPSs　adsorption　capability,　but　also　reveal　the　FeSe2　and　Ni3Se4　are　conductive　to　consecutively　catalyze　the　reduction　of　long-chain　and　short-chain　polysulfide　intermediates,　respectively.　Consequently,　Li-S　batteries　assembled　with　the　CNF@Ni3Se4/FeSe2　interlayers　deliver　remarkable　electrochemical　performance　including　high　reversible　discharge　capacity　(1412.1　mAh　g-　1　at　0.1　C),　excellent　rate　performance　(588.0　mAh　g-　1　at　5　C)　and　good　long-term　cycling　stability　(capacity　fading　of　0.058　%　per　cycle　at　2　C　after　1000　cycles).　More　encouragingly,　a　high　initial　discharge　capacity　of　1039.3　mAh　g-1　can　be　obtained　even　under　a　high　sulfur　loading　of　4.5　mg　cm-　2,　indicating　the　great　potential　and　application　prospects.　This　study　provides　valuable　guidelines　for　developing　advanced　tandem　catalytic　systems　in　Li-S　electrochemistry.